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Message-ID: <97b7fd2f0809090032l188c5d62yf756e59652953352@mail.gmail.com>
Date: Tue, 9 Sep 2008 10:32:27 +0300
From: "Syed Jaffar Hussain" <sjaffarhussain@gmail.com>
To: sharmakdeep_oracle@yahoo.com
Subject: Re: Measuring the impact of Redo Log change
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We have seen significant improvements when we enable CIO option of the JFS2
filesystem where redo logs resides.If you are on JFS2 filesystem, I would
recommend you to have a try with CIO option enable on this filesystem (where
redo logs resides).

Regards,

Jaffar

On Tue, Sep 9, 2008 at 7:32 AM, Deepak Sharma
<sharmakdeep_oracle@yahoo.com>wrote:

> We recently (today) moved the redo logs from RAID5 to RAID1+0.
>
> The obvious reason of doing this is to make things better in terms of
> performance, as RAID1+0 is better suited for read/writes. Someone pls
> correct me if that's not true.
>
> What are different ways to measure the impact of this change?
>
> The platform is AIX, DB is 10.2.0.3 and DB size is 55TB, and 2TB redo is
> generated each day. There are plans underway to reduce the redo generation
> using direct path etc. (so let's not get diverted by that).
>
> We can try measuring the wait event stats using AWR, session stats etc.,
> but what exactly to look for?  'log file switch completion', 'log file
> sync', are some things that come to mind - what else?
>
> Thanks,
> Deepak
>
>
>


-- 
Best Regards,

Syed Jaffar Hussain
Oracle ACE
8i,9i & 10g OCP DBA
RAC Certified Expert

Official Oracle RAC SIG Representative for Saudi Arabian region (
http://www.oracleracsig.org/)
http://jaffardba.blogspot.com/
http://apex.oracle.com/pls/otn/f?p=19297:4:1579866181463918::NO:4:P4_ID:126
----------------------------------------------------------------------------------
"Winners don't do different things. They do things differently."

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<div dir="ltr">We have seen&nbsp;significant&nbsp;improvements when we enable CIO option of the JFS2 filesystem where redo logs resides.<div>If you are on JFS2 filesystem, I would recommend you to have a try with CIO option enable on this filesystem (where redo logs resides).</div>
<div><br></div><div>Regards,</div><div><br></div><div>Jaffar<br><br><div class="gmail_quote">On Tue, Sep 9, 2008 at 7:32 AM, Deepak Sharma <span dir="ltr">&lt;<a href="mailto:sharmakdeep_oracle@yahoo.com">sharmakdeep_oracle@yahoo.com</a>&gt;</span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div><div style="font-family:Courier New,courier,monaco,monospace,sans-serif;font-size:12pt"><div>We recently (today) moved the redo logs from RAID5 to RAID1+0.<br>
<br>The obvious reason of doing this is to make things better in terms of performance, as RAID1+0 is better suited for read/writes. Someone pls correct me if that&#39;s not true.<br><br>What are different ways to measure the impact of this change? <br>
<br>The platform is AIX, DB is <a href="http://10.2.0.3" target="_blank">10.2.0.3</a> and DB size is 55TB, and 2TB redo is generated each day. There are plans underway to reduce the redo generation using direct path etc. (so let&#39;s not get diverted by that). <br>
<br>We can try measuring the wait event stats using AWR, session stats etc., but what exactly to look for?&nbsp; &#39;log file switch completion&#39;, &#39;log file sync&#39;, are some things that come to mind - what else?<br>
<br>Thanks,<br>Deepak<br><br></div></div><br>

      </div></blockquote></div><br><br clear="all"><br>-- <br>Best Regards,<br><br>Syed Jaffar Hussain<br>Oracle ACE<br>8i,9i &amp; 10g OCP DBA<br>RAC Certified Expert<br><br>Official Oracle RAC SIG Representative for Saudi Arabian region (<a href="http://www.oracleracsig.org/">http://www.oracleracsig.org/</a>)<br>
<a href="http://jaffardba.blogspot.com/">http://jaffardba.blogspot.com/</a><br><a href="http://apex.oracle.com/pls/otn/f?p=19297:4:1579866181463918::NO:4:P4_ID:126">http://apex.oracle.com/pls/otn/f?p=19297:4:1579866181463918::NO:4:P4_ID:126</a><br>
----------------------------------------------------------------------------------<br>&quot;Winners don&#39;t do different things. They do things differently.&quot;<br>
</div></div>

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